The present invention pertains to devices for an evacuation of air and gas from the dies used in the casting of pieces.
In the die-casting process, one of the most difficult problems to be solved is the correct and complete evacuation of air and gas from the die for forming the piece. The presence of air and gas is also due, among other things, to the effect of evaporation from cooling and/or of splashes on the surface during the phase of filling of the die. If they are not eliminated, the air and gas can remain included in the casting, compromising the structure and quality of the finished piece.
Various systems for the evacuation of air and gas from casting dies which are connected to a suction apparatus or vacuum apparatus already exist on the market. These prior-art systems do not, however, have adjustability features; therefore, they also do not have the versatility to be adapted to the different conditions of operation that may be found in the casting process.
In fact, in die-casting, the variables may be varied, linked with the velocity of the injection piston, with the state of wear and tear, with the passages of the gate section, with the thicknesses of the mold, which are not always uniform, with the temperatures of the lubricants, with the insistence times, and with the many other modifiable features, all of which together contribute to changing and requiring a specific response of evacuation of gaseous fluids over time and because of the amount.
The object of the present invention is to provide a device, which is improved and which can be readily and easily adjusted, even during use, to effectively regulate the evacuation of air and gas from the casting dies and therefore to efficiently solve the problems stated above of the prior art.
Another object of the present invention is to produce a device for regulating the discharge of air and gas from the casting dies, which has high flexibility and adaptability, with a channel, whose section can be finely adjusted for a correct action of evacuation of air and gas and with the purpose of obtaining the most excellent productivity and quality results possible, which can, moreover, be verified by means of a test analysis of the finished pieces.
In accordance with the present invention a device is provided which comprises two complementary bodies which can be closed face to face one on top of another, which has, between said bodies, an evacuation channel, which is connected, on the one hand, to a casting die, and on the other hand, possibly to a vacuum gearcase, and where said channel has a section that can be adjusted, at least in the direction of its height, by means of a movement of an element that is movable in relation to a static surface with which it contributes to delimiting the said channel. This movable element is arranged between the two bodies of the device facing one another, and the fixed surface of the channel is that of one of these bodies. The movable element can be moved at right angles to the fixed surface by a wedge-shaped member, which is moved by a drive shaft.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.